I think it's actually quite difficult. First of all, you can't truly disregard the megapixel count entirely, because a 36 MP Bayer is clearly going to win over a 4.7 MP Foveon, and a 16 MP Foveon is more than likely going to win over a 16 MP Bayer. And it's certainly possible to pick subject material that favors one technology or the other. And finally, the test needs to be done by someone with expertise in subjective testing and without an axe to grind - and that seems especially hard.